Here is the JDM Air Refiner/Purifier System. There were many variations depending on the year of the Prelude. We also shared these with Legends, Accords, etc.

unit








switch













here are a couple of 5th gen Air Refiners. These babies had lights as well and were over-head models.

JDM Honda Access Air Refiner w/dual dome light












Here is a similar unit installed overhead as oppose to 4th gen which is installed between the rear speakers.



Also note that this is not 5th gen specific, but at the time was available as a Honda Accessory for a wide range of Honda vehicles. Controlled by inbuilt switches and doesn't require a need for a console air refiner switch that was featured in 4th gens.

yeah got one of these havnt wired it in yet though